My understanding is that there is a private party at D-MGM that night, so they will actually be (perhaps not throwing out, but rather) corraling guests out of the park and either into the parking lot or into the Hollywood Hills Amphtheater, assuming Fantasmic! is being performed. I would expect that exiting from Fantasmic! that night would be limited to the backstage exit, and of course once you're in the Hollywood Hills Amphtheater, there will be no returning into the park itself.